Voice processing systems for use in conjunction with telephone networks are well known in the prior art. Such systems typically include an announcing means for generating voice messages that are useful in guiding a caller in how to use the system. A voice recognizer is provided to receive and analyze words spoken by the caller. Current systems generally allow the caller to interrupt the voice messages generated by the system by depressing a particular key on the keypad. Once the system-generated voice message is interrupted, the recognizer can readily respond to the input speech. More sophisticated voice processing systems provide voice prompt interruption through detection of word onset when the caller begins to speak. In the latter case, however, the recognizer cannot recognize any speech input to the system spoken while the outgoing message is being played or is being reflected back into the recognizer, generally because of the amplitude of the message reflection relative to that of the spoken input. Thus if the caller speaks as the prompt is made, the speech might stop the prompt but it cannot be adequately recognized and used by the voice processing system. The inability of the prior art systems to recognize that portion of the caller input spoken concurrently during the playing of outgoing messages or prompts is a significant drawback of such systems.
There has therefore been a long-felt need to provide an enhanced technique for use in a voice processing application wherein a caller's speech occurring during outgoing voice messaging can be recognized and used by the voice processing system.